For organic content, their algorithms (before considering paid reach) are organized around making sure you only see, approximately, what you've actively indicated you want to see (which isn't the same thing as "agree with" -- if you positively engage with things you disagree with, you'll see more of them.)
Of course, Facebook's revenue model is entirely based on people paying -- either via ads-in-the-overt-sense or paid reach for posts -- for more favorable treatment for their content than the relying on the normal algorithms and (in the case of ads-in-the-overt-sense) even the basic opt-in following mechanism would provide, so its not at all the case that it is good at making sure you only see what you agree (or have positively asserted an interest in seeing, even.)
Though they do let you opt out of ads from a particular advertiser or particular ads, so they are arguably fairly good at making sure you do not see what you have actively requested not to see, which is different than only seeing what you agree with (or even want to see.)
I soo wish for "NEVER EVER SHOW ME THINGS LIKE THIS AGAIN" YouTube button. Currently I open one wrong YT link and for the next week google keeps recommending me videos of shitting babies or some 'hot new singer you just need to listen'.